The present invention relates to a digital camera and, more particularly, a digital camera to which new functions can be attached and a function appending method of appending new functions to the digital camera. As such new functions, there are a direct print function for printing picked-up image data with the use of a printer, a communication function for transmitting the image data to terminals located at remote places by using a transmission network, etc.
In recent years, the digital camera (electronic still camera) are developed and on the market, and are now spreading. Normally the picked-up image result by the digital camera (digitized color image data) are printed. A personal computer (abbreviated as “PC” hereinafter) and a printer, a video printer, or the like are employed to output the print.
In the case of the digital camera which employs an internal memory medium to record the image data, an output terminal of the digital camera and an input terminal of PC are connected to each other via a serial cable, then image signals (image data) are installed into PC via an interface such as RS232C to apply the imaging processing, and then the color image are printed by the printer.
In the case of the digital camera which employs a memory card to record the image data, the image data are installed into PC by reading the memory card by a memory card reader (reading device) to apply the imaging processing, and then the color image are printed by the printer. In color printing, in order to print the color image (video) with high precision, print image data generating processing is executed by using programs on the PC side. And then bit map data, which are prepared every print color necessary for drawing, and a control signal are provided to the printer to perform the color printing operation.
The programs for the print image data generating processing are contained in programs which are called a printer driver in a data process module 210 shown in FIG. 10. A normal printer driver 220 contains three groups of programs, i.e., a rasterizer, a color correction module, and a halftone module.
First the JPEG (Joint Photographic Experts Group)-compressed image data are expanded by an expansion program 216 to be stored in a memory, then their Y, U, V components are converted into R, G, B components, and then the images are displayed on a monitor 230 by using an image display/selection application program 218. Then, the user selects the to-be-printed image from the displayed images.
The selected image data are processed by a rasterizer 221 in the printer driver 220. The image data are separated into three primary colors of R (red), G (green), and B (blue) to constitute RGB multitone (e.g., 256 tones) bit image data which are subjected to the raster conversion every color.
The color correction process is then applied to the RGB multitone bit image data, which are subjected to the raster conversion, via a color correction module 222 so as to correlate the image data with printing colors. Thus, RGB multitone bit the image data are converted into printing CMYK multitone bit image data which are separated into C (cyan), M (magenta), Y (yellow) and K (black).
The CMYK multitone bit image data is supplied to a halftone module 223 where halftone process (binarization process) is carried out by the dither method, the error diffusion method, etc. Thus, color allocation or arrangement on the bit map is decided every color, and binary bit maps (binary data tables) are formed respectively. Then, the PC sends the bit map data as well as the printing control signal and the plotting signal to a printer 240. The printer 240 executes a printing operation based on the control signal and the bit map data for each color to reproduce the color image on a recording paper.
Meanwhile, there is the digital camera which has a function for outputting the image as NTSC video signals and thus outputs the image to a video printer by using video signals. Since the video printer effects color adjustment by converting the input video signal into the digital signal once and then converting the digital signal into the analogue signal again, RGB multitone (e.g., 256 tones) bit image data which are separated into three primary colors of R, G, B can be obtained. However, since the D/A conversion in the digital camera and the A/D conversion on the video printer side are repeated, there are such problems peculiar to the analogue technology that the quality of image is easily deteriorated and also the image lacks the stability. Also, normally many application programs other than image (or video) print processing are installed in the PC because of its versatility. Since these application programs and the above printer driver are operated under management of OS such as Windows, MS-DOS (both are trademarks of Microsoft Corporation), etc., when the print processing of the image is performed, the user must execute the command input operation defined by the OS, to load the print processing application program and the printer driver from the storing device (e.g., magnetic disk), which store them, into an internal memory of the PC and to set the PC into the executable state. However, there are such problems that it take a lot of time (so-called an overhead time) to load the command input, the print processing application program, and the printer driver and that it requires time to start up the PC because several minutes are needed at least.
In addition, although the spread of the PC is remarkable, many problems to be solved further are still remain in handling the PC actually. There is an indication that a large majority of the PC owner merely have the PC but they cannot handle the PC. In order to print the resultant image picked up by the digital camera, there are also such problems that there will be caused disadvantages that it is hard to install them or it is not understood how to input the command even if these users buy the image (video) print processing application program and the printer driver and then try to install them into the PC.
Furthermore, there are also such problems that to prepare the expensive PC for merely printing the picked-up image spoils extremely the user's convenience.